/Engine/Source/Runtime/Renderer/Public/SystemTextures.h
Create default 2D/3D/Cube/Array texture (1x1) with specific format and initialize value.
FRDGTextureRef GetDefaultTexture ( [FRDGBuilder](API\Runtime\RenderCore\FRDGBuilder) & GraphBuilder, ETextureDimension Dimension, EPixelFormat Format, float Value )